The invention relates generally to electronic controls for appliances and the like and more particularly to electronic data entry and display arrangements for such controls.
Electronic controls with digital displays and user actuable data entry touch key arrays are now commonly available with a variety of appliances such as microwave ovens, cooktops and ranges. The more commonly used arrangement with microwave ovens involves a key panel with ten numerical keys plus various function keys. The numerical keys are pressed to enter control parameters such as time or temperature. The number keys typically enter data in the order the keys are actuated starting with the most significant digit entered first. Each entry goes initially into the least significant digit position, shifting the preceding entry to the left with each successive pressing of a numerical key, until the desired parameter values are set in the display. Examples of such systems may be found in U.S. Pat. Nos. 4,343,990 and 4,011,428. This approach is satisfactory but requires a relatively large keyboard area and a relatively large number of switches adding to the complexity and cost of the keyboard and control.
Slew entry, a data entry technique in which a display runs through a sequence of numbers or other characters until the desired value or display appears, has long been employed in digital clocks to adjust the time setting and alarm setting. In order to speed up the data entry process, such digital clocks typically include a fast setting key and a slow setting key. To further speed up the process, a forward/reverse key may be provided to permit slewing in either direction. However, the fast setting typically involves a display which sequences so rapidly, particularly at the least significant digit position, that the flickering of that digit is unreadable, annoying and distracting, making it difficult to recognize the desired stopping point.
Slew entry has also been introduced in appliances such as microwave ovens as an improvement which simplifies the keyboard by replacing the ten numerical keys with slew pads. U.S. Pat. No. 4,158,759 discloses an arrangement in which a single slew pad is associated with each digit position in the display. Pressing one of the pads causes the associated digit position to cycle through numbers 0-9 until the key is released to stop the displayed digit at the desired value.
In U.S. Pat. No. 4,572,935 two keys, a temperature-up key and a temperature-down key, are provided for entering temperature set point data for a microwave oven. In one embodiment the display is set to 200.degree. C. in response to the initial touching of either key. Thereafter, each time the up or down key is pressed the value increases or decreases by 5.degree. C.
U.S. Pat. No. 4,308,443 discloses a control for an induction cooktop which enables the user to select the relative cooking power as a percentage. Hi, Lo and Off pads are provided for each surface unit. Touching the Hi pad causes the numerical display of percentage to increase in increments of ten as long as the Hi pad is touched. The displayed value decreases in increments of one as long as the Lo pad is touched.
U.S. Pat. No. 4,399,352 discloses a microwave oven which uses a key arrangement similar to the aforementioned '759 patent to enter time data, and which has a separate temperature set point display comprising nine segments, each representing a 10.degree. temperature interval with the enter display covering the range from 170.degree. C. to 250.degree. C. A single temperature key increments the display by 10.degree. C. per touch, or at a rate of one segment (corresponding to 10.degree. C.) per second if continuously touched.
It is a primary object of the present invention to provide an improved data entry and display control arrangement for appliances which enables the user to quickly and accurately enter the desired time and/or temperature information using an up slew key and a down slew key, with a display which changes at a comfortable rate eliminating the rapid flickering in the least significant digit position.
It is a further object of the present invention to provide an improved data entry and display control arrangement of the aforementioned type which enables the user to adjust the update rate of the display.